/*
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.everrest.core.impl.provider;

import org.everrest.core.provider.EntityProvider;
import org.everrest.core.util.Logger;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.Provider;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

/**
 * @author <a href="mailto:andrew00x@gmail.com">Andrey Parfonov</a>
 * @version $Id: DOMSourceEntityProvider.java 285 2009-10-15 16:21:30Z aparfonov
 *          $
 */
@Provider
@Consumes({MediaType.APPLICATION_XML, "application/*+xml", MediaType.TEXT_XML, "text/*+xml"})
@Produces({MediaType.APPLICATION_XML, "application/*+xml", MediaType.TEXT_XML, "text/*+xml"})
public class DOMSourceEntityProvider implements EntityProvider<DOMSource>
{
   /** Logger. */
   private static final Logger LOG = Logger.getLogger(DOMSourceEntityProvider.class);

   /** {@inheritDoc} */
   public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return type == DOMSource.class;
   }

   /** {@inheritDoc} */
   public DOMSource readFrom(Class<DOMSource> type,
                             Type genericType,
                             Annotation[] annotations,
                             MediaType mediaType,
                             MultivaluedMap<String, String> httpHeaders,
                             InputStream entityStream) throws IOException
   {
      try
      {
         DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
         factory.setNamespaceAware(true);
         Document d = factory.newDocumentBuilder().parse(entityStream);
         return new DOMSource(d);
      }
      catch (SAXParseException saxpe)
      {
         // if can't read from stream (e.g. steam is empty)
         if (LOG.isDebugEnabled())
         {
            LOG.error(saxpe.getMessage(), saxpe);
         }
         return null;
      }
      catch (SAXException saxe)
      {
         throw new IOException("Can't read from input stream " + saxe);
      }
      catch (ParserConfigurationException pce)
      {
         throw new IOException("Can't read from input stream " + pce);
      }
   }

   /** {@inheritDoc} */
   public long getSize(DOMSource t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return -1;
   }

   /** {@inheritDoc} */
   public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return DOMSource.class.isAssignableFrom(type);
   }

   /** {@inheritDoc} */
   public void writeTo(DOMSource t,
                       Class<?> type,
                       Type genericType,
                       Annotation[] annotations,
                       MediaType mediaType,
                       MultivaluedMap<String, Object> httpHeaders,
                       OutputStream entityStream) throws IOException
   {
      StreamResult out = new StreamResult(entityStream);
      try
      {
         TransformerFactory.newInstance().newTransformer().transform(t, out);
      }
      catch (TransformerConfigurationException e)
      {
         throw new IOException("Can't write to output stream " + e);
      }
      catch (TransformerException e)
      {
         throw new IOException("Can't write to output stream " + e);
      }
      catch (TransformerFactoryConfigurationError e)
      {
         throw new IOException("Can't write to output stream " + e);
      }
   }
}
